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Electronic and Structural Properties of Tungsten Bronzes
Author(s) -
Bonnet A.,
Conan A.,
Morsli M.,
Ganne M.,
Tournoux M.
Publication year - 1988
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221500125
Subject(s) - bismuth , antimony , condensed matter physics , seebeck coefficient , fermi level , materials science , delocalized electron , tungsten , electrical resistivity and conductivity , electronic band structure , conductivity , fermi energy , variable range hopping , atmospheric temperature range , thermal conduction , chemistry , electron , physics , thermal conductivity , metallurgy , thermodynamics , composite material , organic chemistry , quantum mechanics
Transport coefficient measurements (electrical conductivity and thermoelectric power) are performed on compact bars of antimony and bismuth tungsten bronzes in polycrystalline form over the temperature range 100 to 500 K. Experimental results are discussed in comparison with those obtained recently on antimony and bismuth molybdenum bronzes in which two inverted narrow levels pin the Fermi level near the midgap. A single band model accounts for all the experimental results. In Bi 4 W 20 O 62 the conduction mechanisms are governed by hopping in states near the Fermi energy. It is shown that variable range hopping occurs at low temperature whereas next neighbour hopping takes place at higher temperature. This band may be formed by the overlap of some broadened levels. The antimony phases are characterized by a non‐activated electrical conductivity and small TEP. These results are interpreted under the assumption that this narrow band broadens: this wide band is less than half‐filled and the electronic states are highly delocalized leading to “metallic” behaviour.